Gas fired water heaters optionally include a damper that controls the passage of exhaust gases from a combustion chamber. An example of such a water heater is described in U.S. Pat. No. 6,684,821 to Lannes et al.
The Lannes patent discloses an improved water heater in which energy can be sustained within the water heater to allow for the reliable operation of the water heater even in the event of a power failure. When the temperature of water in the tank of the water heater reaches the set point of a thermostat, the thermostat switches, opening the circuit between a wire supplying power to the thermostat and a wire leading to a damper, and closing the circuit between the wire supplying power to the thermostat and the wire connected to a pressure switch. When the gas is no longer flowing through a manifold, the pressure switch closes, completing a circuit between the thermostat and the wire leading to the damper. The completion of this circuit supplies power to the damper motor so that a damper vane moves to the closed position.
Despite improvements in gas-fired water heaters such as those disclosed in the Lannes patent, there remains a need for continued improvements.